The present invention relates to a surgical material comprising surgical filaments which is useful in combating bone defects.
A number of materials are known for use in surgery. They can be either resorbable or non-resorbable in the body. For example, in the form of filaments or wires, they are resorbable or non-resorbable suture material, or, in the form of plates, films, pins or screws, they are used for supporting or joining parts of the skeleton. It has also already been proposed to use filament material in the form of woven, plaited or knitted textile structures to support a damaged liver, kidney or other organs. Furthermore it has been proposed to admix resorbable filaments, in the form of finely chopped pieces, into commercially available bone cements.
Commercially available bone cements of this type which are based on acrylates or methacrylates are used for filling bone defects, in so-called linking osteosyntheses, or in the implantation of endoprostheses. It is disclosed that the incorporation of resorbable filament pieces in implanted endoprostheses, after these filament pieces have been resorbed, results in pores in the non-resorbable bone cement into which body tissue can grow. It is stated that an improved long-term stability of the prosthesis is achieved in this way.
However, it is possible for endogenous tissue to grow in only those pores produced from a piece of polymer filament which happens to extend to the surface of the cement from where it can be resorbed. The filament pieces which lie inside the cement, on the other hand, cannot be reached by body fluids and resorbed. They, therefore, make no contribution to the prosthesis becoming in-grown with body tissure. Because of this, it can be expected that the long-term stability of a prosthesis which has been implanted using a bone cement to which chopped pieces of resorbable polymer filaments have been added is at best slightly improved. Since, moreover, the filament pieces incorporated must be relatively short to enable them to be mixed with the cement at all, they are also not expected to result in any improvement in the elasticity and stability of the cement socket formed around the implanted prosthesis. Specifically, in more than 60% of the cases in which femur shaft prostheses and acetabulum implants become loose, the cement socket is not able to withstand the mechanical stresses. In most cases, the cement socket is ruptured or fractured by the metal shaft or by the plastic acetabulum.